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Brandon Boughen: Pasture weeds can be controlled

Pasture management is the topic I spend the majority of my time on. Whether I’m on a site visit in someone’s pasture or a plant is brought to my office to be identified, the question is usually the same; what is it and how do I kill it?

The drought is a big factor but can’t be blamed for it all. Overgrazing of pasture and poor management is more to blame. Identifying these weeds is the first step with control.

Let’s start by answering the question what is a weed? Perhaps the best definition of a weed is a plant out of place, a plant that is growing where you don’t want it. This could be in a pasture, garden or lawn. Not all weeds are bad (just undesirable), like sunflowers in a cornfield are considered weeds to a farmer, as is Bermuda grass in a vegetable garden to the gardener.

Weeds can be grouped into two major categories — grasses and broad leaves. Weeds can compete with pasture grasses for water, nutrients and sunlight. They can also harbor insects and plant diseases. Some weeds are toxic and can cause livestock to become ill or die.

Weed seeds can remain dormant in the soil for many years, and then germinate when conditions are right. When weeds appear, controlling them can be achieved by many different methods. Prevention can be accomplished by planting weed free seed and/or by using a pre-emergent herbicide. In worst cases eradication of the invasive weed may mean complete reestablishment of the pasture.

Non-re-establishment control methods may involve limited use of herbicides, cultivation, mowing or maintenance of a vigorous pasture grass that will crowd out weeds.

Mowing weeds with a rotary mower can be risky, as it usually causes the weeds to produce their leaves closer to the soil. If you decide to mow, it should be done when weeds are in the bud or pre-bloom stage to reduce seed production of the invasive plant.

If a herbicide is used, you must first identify the plant that is to be controlled to properly choose the right chemical. Herbicide application rates will vary by weed species and plant maturity. Some herbicides require a pesticide applicator license to purchase and apply. When using chemicals, it is very important to read the label and follow the directions closely, to prevent injury to livestock or humans or damage from spray drift. Federal and State law controls the use of restricted and state-limited herbicides.

Pasture weed control will increase forage production on the average of one pound for every pound of weeds controlled. This increase can be equivalent to the application of 40 to 60 pounds of nitrogen per acre. The best method of weed preventive control is to maintain a healthy and well-fertilized stand of pasture grass.

To help landowners learn to identify common pasture weeds and responsible use of herbicides, the Denton County Agriculture Committee will conduct it’s spring pasture weed ID and control workshop from 9 a.m. to noon May 10 at the Sanger High School cafeteria. To register, call 940-349-2889. Registration deadline is Wednesday.

BRANDON W. BOUGHEN, MAg, is the Denton County extension agent with Texas A&M AgriLife Extension Service. He can be reached at 940-349-2894 or by e-mail at